If you have leak at the pump you woudl see it. I don't understand why you'd change the pump without seeing the leak first,
Shurflo pumps don't have bellows like a Vacuflush pump (unless you have th type of pump with external motor and belt) but they do have a diaphragm inside which has a limited life. Some may have a week hole to allow water to leak out when that fails but many do not and water is contained in th pump, ruining the motor.
It's a easy to eliminate the pump, just turn it off the next time you leave the boat and see if you find water when you return,
Hard to know with so few details but I doubt your pump is the source of the leak. More likely to be a pluming leak or rain leak ASSuming it is not coming from the outside of the hull